The present invention relates generally to electrical connectors, and particularly to electrical connectors suitable for underwater use.
Electrical connectors are commonly used for connecting the wires of one cable to the corresponding wires of a similar cable. Typically, the connector comprises plug and socket type connector shells each containing an insert body carrying a plurality of electrical contacts. One of the insert bodies will have a series of projecting electrical pin contacts, while the other insert body will have corresponding pin receiving socket contacts. When the mating connector shells are secured together, the contact pins will be engaged in the corresponding sockets. The cable wires are soldered to contact or solder projections at the rear end of each of the insert bodies. The insert bodies are provided with any number of contact pins or sockets, according to the type of electrical cable to be connected, and they are releasably mounted in the respective connector shells so that different contact carrying inserts can be mounted in the same connector shell according to the particular connection to be made.
One problem with such connectors is maintaining the insert bodies in the correct relative angular orientation so that the pins will slide smoothly into the sockets as the shells are connected together. Any misalignment will result in damage to the pins during the mating procedure, and may result in an improper electrical connection which could result in damage to electrical equipment connected via the connector.
Thus electrical connectors of this type are generally provided with key arrangements for maintaining accurate relative angular orientation between the respective parts as they are connected together. U.S. Pat. No. 4,235,498 of Snyder, for example, shows a plug and socket type connector in which the socket has internal keyways for engagement with corresponding projecting keys on the outer surface of the plug as they are connected together. Where the insert bodies are releasably mounted in the plug and socket shells, they must also be provided with a keying arrangement to ensure accurate orientation. Thus it is known to provide internal keyways in the plug and socket shells for engagement with corresponding projecting keys on the insert bodies as they are inserted. One problem with this is that since the keys and keyways are internal, and thus within the shell as the insert body is inserted, it is difficult to accurately align the key and keyway. The key must first be visually aligned before inserting the insert body, at which point it can no longer be seen.
This alignment is even more difficult in cases where the insert body is inserted through the rear end of the connector shell, so that the connected cable is in the way of any clear view of the insert key as it is inserted. Although insert bodies are frequently arranged to be insertable through the front end of the respective connector shell, rear end insertion is used in some designs, particularly in miniature underwater connectors, making alignment difficult. In some cases, the key will be sheared off if not correctly aligned. Thus, if the key and keyway are misaligned, the key may be damaged if the insert body is forced in and the insert contacts may not be in the correct orientation.